''Amphinectomys savamis'', also known as the Ucayali water ratMusser and Carleton, 2005 or amphibious rat,Duff and Lawson, 2004 is a

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

from the

Peruvian Amazon Peruvian Amazonia (), informally known locally as the Peruvian jungle () or just the jungle (), is the area of the Amazon rainforest in Peru, east of the Andes and Peru's borders with Ecuador, Colombia, Brazil, and Bolivia. Peru has the second-l ...

. It is placed as the only member of

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

''Amphinectomys'' in the tribe

Oryzomyini Oryzomyini is a tribe of rodents in the subfamily Sigmodontinae of the family Cricetidae. It includes about 120 species in about thirty genera,Weksler et al., 2006, table 1 distributed from the eastern United States to the southernmost parts of S ...

of family

Cricetidae The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, muskrats, and New World rats and mice. At over 870 species, it is either the largest or second-largest family ...

. It is similar to '' Nectomys'', but its discoverers considered it to be different enough (with more expansive interdigital webbing and a significantly broader interorbital region) to require its own genus. When it was described as a new genus in 1994, knowledge of the variation within ''Nectomys'' was much more limited than it is now, and it has been suggested that the status of the taxon be re-examined considering this new information. The species's

karyotype A karyotype is the general appearance of the complete set of chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is discerned by de ...

, 2n = 52, falls within the known range of ''Nectomys'' (2n = 38 - 59).

References

Literature cited

*Duff, A. and Lawson, A. 2004. Mammals of the World: A checklist. New Haven, Connecticut: Yale University Press, 312 pp. *Malygin, V.M., Aniskin, V.M., Isaev, S.I. and Milishnikov, A.N. 1994. ''Amphinectomys savamis'' Malygin Gen. et sp. n., a new species and a new genus of water rat (Cricetidae, Rodentia) from Peruvian Amazonia. Zoologicheskii Zhurnal 73:195-208. Mammals of Peru Oryzomyini Mammals described in 1994 Aquatic mammals {{Sigmodontinae-stub